Apparatus for treating liquids with light rays



Ap 6, 1954 AE. NICHOLSON 2,674,697

APPARATUS FOR TREATING LIQUIDS WITH LIGHT RAYS Filed June 23, 1950 3 Sheets-Sheet l Inventor EMMETT NICHOLSON By 6/;w, flo W WW6 Attorneys April 6, 1954 E. NICHOLSON 2,674,697

APPARATUS FOR TREATING LIQUIDS WITH LIGHT RAYS Filed June 23, 1950 5 Sheets-Sheet 2 FIG. 2

FIG. 8

Inventor EMMETT NICHOLSON y Ma Attorneys Patented Apr. 6, 1954 UNITED STATES PATENT OFFICE APPARATUS FOR TREATING LIQUIDS WITH LIGHT RAYS Emmett Nicholson, Dunedin, Fla.

Application June 23, 1950, Serial No. 169,879

6 Claims. 1

This invention relates to the treatment of liquids with light rays, and more particularly to apparatus for sterilizing liquids by means of ultra-violet light.

It has long been known that ultra-violet light, especially when lying within a certain range of wave length, provides a potent and efiective means for killing bacteria, and for sterilizing liquids. The problem has been to devise a practical and efficient method for subjecting the liquid to the action of the light rays in such a manner that relatively low cost apparatus shall be capable of a relatively large output.

In my prior Patent No. 2,499,153, issued February 28, 1950, I have disclosed apparatus comprising a plurality of horizontal rollers over which the liquid is caused to flow by rotation of the rollers in a thin film or layer, while exposed to light rays from straight-bodied lamps extending parallel with and as close as practicable to the rollers. While this apparatus operates well, and produces very satisfactory results, the lamps are necessarily placed at a considerable distance from the surface over which the liquid is flowing, due to the desirability of illuminating as large an area as possible, and this renders the killing power of the rays less effective than it would be if the lamps could be arranged closer to the liquid film.

An object of the present invention is to devise an arrangement in which the source of light is disposed in close proximity to the film of liquid, whereby its efliciency is greatly increased, and whereby, because of the intensity of the radiation at such close range, the liquid can be caused to flow at high speed, thus increasing the output per unit of area.

To this end, and in its broadest aspects, the invention contemplates causing a film of liquid to flow over one side of a transparent sheet, and disposing tubular, electric lamps on the other side of said sheet, substantially in contact therewith, so that the liquid is separated from the lamps only by a distance equal to the thickness of said sheet.

More specifically, the invention contemplates the provision of a centrifugal sterilizer comprising a pair of horizontally disposed, co-axial, disclike members constituting a stator and rotor, mounting arcuate, tubular lamps in the face of one or both members, and introducing the liquid between said members at the center thereof, whereby it is caused to flow radially of said members as the rotor is turned at high speed.

In previous attempts to utilize ultra-violet lamps for the sterilization of-liquids, it has been found, as set forth in my above mentioned prior patent, that the operation of such lamps tends to generate ozone in the surrounding atmosphere, and the presence of ozone is highly objectionable when treating liquids such as milk.

Another object of the present invention is to provide ultra-violet light sterilizing apparatus so constructed that there is practically no air in contact with the liquid while being subjected to the action of the light rays, so that very little, if any, objectionable ozone is generated.

A still further object of the invention is to devise a novel and improved type of ultra-violet lamp, the lamp comprising a tube bent into a plu-- rality of convolutions in the form of a flat spiral.

In order that the invention may be readily understood, reference is had to the accompany-- ing drawings forming part of this specification and in which:

Fig. l is a vertical, central section through oneform of my improved apparatus, parts being shown in elevation.

Fig. 2 is a plan view of the rotor member shown in Fig. 1, the circular sheet or cover being omitted for the sake of clearness.

Figs. 3, 4 and 5 are fragmentary, vertical sections on an enlarged scale through a portion of the rotor member, these views illustrating three slightly different modified constructions.

Fig. 6 is a similar view showing a still further modified construction.

Fig. 7 is a plan view similar to Fig. 2 but showing a modified arrangement, and

Fig. 3 is a fragmentary, vertical section on the line 88 of Fig. '7 showing the lamp terminals.

Referring to the drawings in detail, my improved centrifugal apparatus comprises a suitable upright base I on which is mounted, by means of bolts ll, a bowl 2, these parts being preferably formed of cast metal. The bowl 2 has at its upper edge an outwardly projecting annular flange 4 on which rests an annular supporting ring 5, to which is secured by means of bolts 1 a clamping ring 6. Held between the supporting ring 5 and clamping ring 6 is the edge of a discshaped stator member 9, a suitable packing 8 being preferably interposed. The stator member 9 is provided with a peripheral downwardly projecting lip it for a purpose hereinafter explained.

On the lower face of this stator member is mounted a special ultra-violet lamp, hereinafter described more in detail in connection with the lamp carried by the rotor member, but comprising a tube 1 I wound in the form of a spiral, the turns being separated by partition strips l2. At

the inner and outer ends of the spiral tubular lamp are provided suitable terminals I3, adapted to be connected to a source of electrical energy of the proper voltage. This stator member is preferably made of a suitable type of glass such as Pyrex, or it may be of metal. The stator is provided with an upstanding central inlet opening 9 through which the liquid to be treated is introduced.

A circular sheet or cover 9* is secured over the lower face of the stator 9 just beneath the tubular lamp, this sheet or cover being formed of some material such as a special glass which is substantially transparent to ultra-violet rays.

Immediately below the above described stator is positioned a rotor Hi, having a peripheral lip I5, and. similar in size and shape to the stator. This rotor is of course disposed adjacent and parallel with the stator. A tubular, spiral lamp II is mounted in its upper face, the convolutions being separated by strips I2, and the lamp being covered by a circular, transparent sheet I i The particular type of lamp illustrated in Fig. l is that best shown in Fig. 5. By reference to this figure, it will b seen that the strip or strips ii! are separately formed and are interposed between the convolutions of the spiral lamp. They serve to support the sheet or cover Id which is firmly secured to the outer rim of the disc I4 and is in substantial contact with the lamp tube.

Fig. 2 diagrammatically illustrates the construction and arrangement oi the special lamp II. This lamp consists of a tube formed of a special glass capable of freely transmitting ultraviolet light, and wound into the form of a spiral. For the sake of clearness, the spacing strips or partitions have been omitted from this view. In practice, the lamp tube may be on the order of one inch in diameter, and the coiled or spirally wound tube may be as much as thirty or forty feet in length. The type of lamp which I prefer to employ is that known as a low pressure, mercury vapor, germicidal lamp, and a lamp of this character, thirty or forty feet long, as described, may require as much as 15,000 volts, but operates at a relatively small wattage so that only a slight amount of heat is generated.

Referring again to Fig. l, the rotor it, which, like the stator, is preferably made of a special glass such as Pyrex, is formed with a central hub it having a projection cemented or vulcanized into a socket member I I carried at the upper end of a vertical shaft 29-. Th member I! has a threaded socket I8 in which the threaded end I9 of the shaft engages, and a set screw 2!, extending through the member I7, engages the shaft to lock the parts in position. It will be apparent that by loosening the set screw 2 I and turning the rotor on the shaft 2! the rotor may be adjusted vertically until the correct clearance between itself and the stator is obtained, and the set screw may be then tightened. In this way a very accurate adjustment may be made.

The shaft is supported at its upper end in a bearing 22, shown as a ball bearing, and at its lower end in a bearing 23, carried by a plate 24, secured by bolts to the base I. A pulley 26 is secured to the lower end of the shaft, .by which it may be driven. The base is provided with an opening I through which the driving belt extends, and the bowl 2 is also formed with an opening 2 for affording access to the interior thereof.

Clamped between the hub I6 and the socket member I7 is a plate 30 of insulating material and supported from this plate below the same are 4 a pair of concentric slip rings 3|. These rings are connected with the terminals I3 of the lamp as by means of binding posts 32. Brushes 33, carried by an insulating support 34, bear against the slip rings SI and are connected to a suitable source of current as by means of wires 35.

Instead of constructing the disc members as shown in Figs. 1 and 5, I may construct them as shown in Fig. 4. In this figure the disc I4 is shown as provided with a spiral groove I2 in which the convolutions of the tubular lamp I I are laid, the grooves being separated by partitions I2 formed integral with the disc. This space in the grooves between the tube and the sheet M may be filled with a transparent cement or compound I4 to exclude air.

Again, instead of forming the lamp of a round tube, it may be formed of a tube rectangular or square in cross section as shown at I I" in Fig. 3. This has the advantage that the outer fac of the tube is flat and hence lies in close contact with the sheet or cover HI. In this Fi 3 I have not illustrated any partitions between the convolutions of the tube, and such partitions may not be necessary.

Still again, when using tubes of rectangular cross section, it may in some cases not be necessary to employ a cover sheet, such as I4 This modification is illustrated in Fig. 6, in which the tube convoluti-ons are shown as wound very closely together, with the cracks between them, and between the tube and the body of the disc, filled with a suitable waterand acid-proof compound or cement I4". When accurately mad and assembled, the face of the rotor, formed by the spiral tube and filling compound, presents a flat, smooth, unbroken surface, over which the liquid being treated can freely flow. In this modification, the body of the disc is preferably made of glass similar to that of the lamp tube, and having the same eo-eflicient of expansion.

Finally, instead of employing a lamp consisting of a single spirally wound tube, I may employ a series of concentric lamps each C-shaped as shown in Fig. 7. Each of these lamps will of course be provided with its own terminals as shown at It in Fig. 8. As illustrated in this figure, the ends of the tubular lamps II a project downwardly from the disc I 3, and the projecting ends, which house the terminals I3 are preferably surrounded by a composite glass structure Iii to prevent breakage.

In order to equalize the weight and balance the rotor, the lamp terminals are arranged alternately on opposite sides of the center, as indicated in Fig. 7.

When using C-shaped lamps such as illustrated in Fig. '7, the disc and partitions may be constructed either as shown in Fig. 4 or Fig. 5 or tubes of rectangular cross-section such as shown in Fig. 3 may be employed.

Secured to the inside of the bowl 2 is a supporting ring 28 and on this ring is supported an annular sheet metal trough 21. This trough is so shaped that the inner wall underlies the lips I0 and I5 of the stator and rotor members respectively, so that liquid introduced into the inlet 9' and escaping from the periphery of the disc members will be discharged into the trough 21. From this trough it flows through a pipe 29 into any desired receptacle.

From the foregoing, it will be understood that when the rotor is being driven at high speed, liquid entering the apparatus through the inlet 9 is impelled centrifugally outwardly through the space between the stator and rotor members, and the rate at which the liquid is impelled is proportional to the speed at which the rotor is driven. The liquid thus passing between the stator and rotor in the form of a thin film is exposed on both sides to the action of ultra-violet light. In the modifications shown in Figs. 1, 3, 4 and 5, the light is transmitted through the sheets or covers 9 and M while with the construction illustrated in Fig. 6, the film is in actual contact with the lamp itself. Owing to the close proximity of the liquid film to the source of light, the action of the ultra-violet radiation will be extremely efficient.

Due to the small clearance between the stator and rotor, and to the rotation of the rotor, turbulence will be created in the film of liquid and the liquid will be stretched and turned over and over while passing between the lamps. Thus, no part of the liquid will escape treatment.

As the space between the lamps in the stator and rotor is completely filled with liquid, so that there is no air present, ionization of the component parts of the air and the generation of ozone is completely prevented. Thus, one of the major difficulties heretofore encountered in the treatment of liquid food products with ultraviolet light has been overcome.

While I have shown and described both the stator and rotor as equipped with the ultra-violet lamps, and while this is the most efficient arrangement, since it serves to subject both sides of the liquid film simultaneously to the light rays, it will be understood that the invention is not limited to such an arrangement, but that I contemplate also the use of apparatus in which only one of the members, preferably the stator, is provided with lamp means. In this case the rotor will be simply a disc having a smooth face, and its rotation will cause the same turbulence of the film as described above, and with the same results. Omission of the lamp means from the rotor, where this is practicable, greatly simplifies the problem of supplying electric current to the apparatus, and reduces the cost.

What I claim is:

1. Apparatus for treating liquids with ultraviolet light rays comprising a pair of co-axial disc like members disposed parallel with each other and in close proximity, one of said members having formed in its face adjacent the other member a spiral groove substantially co-extensive therewith, a transparent, circular sheet overlying all of the convolutions of said groove, ultra-violet light emitting means within said groove, means for introducing liquid into the space between said sheet and the other member, and means for rotating one of said members relative to the other, so as to force the liquid centrifugally through said space radially over the surface of said sheet past all of the said convolutions in succession.

2. A centrifugal sterilizer comprising disc like stator and rotor members in close proximity, one of said members having on its face adjacent the other member a separately fabricated tubular ultra-violet lamp arranged in the form of a spiral, means for supplying current to the terminals of said lamp, and means for introducing liquid into the center of the space between said members in such manner that it flows radially outward past all of the convolutions of said lamp in succession.

3. A centrifugal sterilizer comprising disc like stator and rotor members, each of said members having on its face a tubular ultra-violet lamp arranged in the form of a spiral, a transparent sheet overlying each lamp, means for supplying current to the terminals of said lamps, and means for introducing liquid into the center of said stator, whereby it hows out radially through the space between said sheets.

4. A centrifugal sterilizer in accordance with claim 2 in which the tubular lamp is of rectangular section with a fiat outer surface.

5. A centrifugal sterilizer comprising disc-like stator and rotor members in close proximity, one of said members having on and substantially coextensive with its face adjacent the other member, a tubular, ultra-violet lamp arranged in the form of a spiral, and means for introducing liquid into the center of the space between said members in such manner that it flows radially over the surface of said lamp.

6. A centrifugal sterilizer including parallel disc-like stator and rotor members in close proximity, one of said members having distributed over its face adjacent the other member tubular, ultra-violet lamp means comprising a plurality of arcuate convolutions, means for rotating said rotor member, and means for introducing liquid into the center of the space between said members in such manner that it is forced radially outward past all of said convolutions in succession.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,068,898 Henri et a1. Jan. 29, 1913 1,145,140 Henri et a1. July 6, 1915 2,072,417 Berndt et al Mar. 2, 1937 2,119,784 Johnston June 7, 1938 2,280,841 Ogden Apr. 28, 1942 2,338,388 Whitman Jan. 4, 1944 2,406,146 Holmes Aug. 20, 1946 2,446,712 McIllvaine Aug. 10, 1948 2,507,490 Cohen May 16, 1950 FOREIGN PATENTS Number Country Date 328,410 Great Britain May 1, 1930 669,400 France Nov. 15, 1929 

